Field of the Invention
The invention relates in general to a display panel and a display device using the same, and more particularly to a display panel with an oxide semiconductor top channel, and a display device using the same.
Description of the Related Art
The material of thin-film transistor (TFT) channel commonly used in display panel comprises poly-silicon and amorphous silicon (a-Si). The poly-silicon TFT component has a higher mobility (>100 Vs/cm2) but has a higher manufacturing cost, too. To the contrary, the a-Si TFT component has a lower manufacturing cost but has a lower mobility (<1 Vs/cm2), too.
The oxide semiconductor formed by amorphous indium gallium zinc oxide (a-IGZO), which possesses excellent electrical properties (for example, the mobility is between 10-20 Vs/cm2, the small diversity of the threshold voltage, and the switching function) and can be used as an electron channel layer, has attracted considerable attention. When forming a channel layer, current TFT design (for example, the bottom-gate design such as back channel etching (BCE) and a channel protection (CHP), and the top-gate design such as low temperature poly-silicon (LTPS)) requires an extra manufacturing step such as a chemical vapor deposition (CVD) process and a plasma process. These extra processes may cause oxygen deficiency to the oxide semiconductor. Oxygen deficiency makes the starting voltage (Vgh) drift or the sub-threshold swing (SS) become too large, hence affecting the properties of electron channel of the oxide semiconductor.